Also known as Funnel Web Tarantulas, they are characterized by not having a rastellum (closely spaced parallel ridges) on each of their Chelicerae. Their carapace (upper shell of the part of the spider forward of its abdomen) is characterized by the head region not being higher than the thoracic region. They have a thoracic groove that is a circular pit. Their anterior spinnerets (silk-extruding organs) are very much shorter than their posterior spinnerets have three segments of about equal length.